PowerPoint Presentation: Indirect Tooth-Colored Restoration Level 5 2012-2013 Republic of Yemen University of Sciences & Technology College of Medical Sciences Dentistry College PowerPoint Presentation: Acknowledgement Dr. Nashwan Mohamed.: Dr. Nashwan Mohamed. Lecture outline: L ecture outline Introduction Indications Contra-indications Advantages Disadvantages Clinical procedures CAD/CAM Common problems and solutions Direct Restorations Vs. Indirect Restorations: Direct Restorations Vs. Indirect Restorations Direct Restoration Indirect Restoration Direct Restorations Vs. Indirect Restorations: Direct Restorations Vs. Indirect Restorations Direct restorations : This technique involves placing a soft or malleable filling into the prepared tooth and building up the tooth before the material sets hard . Indirect restorations : Restorations are fabricated outside of the mouth. Most indirect restorations are made on a replica of the prepared tooth in a dental laboratory by a trained technician . Introduction : Introduction Inlay : involves the occlusal and proximal surface of a posterior tooth and may cap one or more but not all of the cusps. Introduction : Introduction Onlay : It is type of restoration that involve the proximal surface of a posterior tooth and all of the cusps. Indication : Indication The indications for inlay and onlay restorations relate to a combination of esthetic demands and size of the restoration and include the following: Esthetic indirect tooth colored restoration are indicated for class I and for class II restoration located in the areas of esthetic importance for the patient. Largely defected previous restorations. Economic factors. Uncooperative patients. Contra-Indication : Contra-Indication Contra-Indication for indirect tooth-colored restorations include: Heavy occlusal force. Inability to maintain a dry field , adhesive techniques require perfect moisture control to ensure successful long term clinical result. Inability to have a adequate isolation. Advantage: Advantage Improved physical properties. Wear resistance. Reduced polymerization shrinkage. Ability to strengthen remaining tooth structure. Biocompatibility and good tissue response . Disadvantage: Disadvantage Increased cost and time. Technique sensitivity. Brittleness of ceramic. Low potential for repair. Difficult intra oral polishing. Clinical procedures: Clinical procedures Tooth preparation. Impression. Temporary restoration. Try-in and cementation. Finishing and polishing. Tooth preparation : Tooth preparation As a first clinical step, the patient should be anesthetized and the area isolated with rubber dam. The compromised restoration (if present) is at this point completely removed, and/or all the caries is excavated. The walls are then restored to a more nearly ideal form with a light-cured glass- ionomer liner/base or a composite restorative material . Tooth preparation : Tooth preparation the occlusal reduction for capping cusps 1.5-2mm. The amount of axial wall reduction for ceramic or composite restoration1-1.5mm. All margins should have 90 degree cavosurface angle. Line and point angle should be well rounded to avoid stress concentration. Tooth preparation : Tooth preparation The carbide bur or diamond used for tooth preparation should be a tapering instrument that creates occlusally divergent facial and lingual walls. Gingival-occlusal divergence should be greater than 2-5 degree. Any isthmus and any groove extension be at least 1.5 mm wide to decrease the possibility of fracture. Tooth preparation : Tooth preparation Small under cut if present can be blocked out by glass- ionomer cement. The pulpal floor should be smooth and flat . Following removal of extensive caries from any internal wall the wall is restored to more nearly ideal form with glass- ionomer cement. Tooth preparation : Tooth preparation Proximal box: The facial, lingual and gingival margins of the proximal boxes should be extended to clear the adjacent tooth by at least 0.5mm. Take great care to have the minimum possible extension of the gingival margin, since the margins in enamel are greatly preferred for bonding. When the facial or lingual surface are affected by caries or other injury extend the preparation with gingival shoulder to include the defect. Impression : Impression Most tooth-colored indirect inlay/onlay systems require an impression of the prepared tooth and the adjacent teeth as well as interocclusal records, which allow the restoration to be fabricated on a working cast in the laboratory . Temporary restoration : Temporary restoration Advantages of the temporary restoration: The temporary protects the pulp-dentin complex in vital teeth . Maintains the position of the prepared tooth in the arch . And protects the soft tissues adjacent to prepared areas . Temporary restoration : Temporary restoration The temporary restoration can be made using conventional techniques and acrylic resins or bis-acryl composite materials. Care should be taken to avoid the bonding of the temporary material to the preparation at this phase of the procedure. A lubricant of some sort may be applied to the preparation if desired especially if a resin-based material was used to block out undercuts and level the walls of the preparation. Temporary restorations for PFM and cast gold restorations typically are cemented with eugenol-based temporary cements. Temporary restoration : Temporary restoration However, eugenol is believed to interfere with resin polymerization and could potentially reduce the adhesion of the permanent composite cement to tooth structure .. use of a non-eugenol temporary cement is recommended. when the temporary phase is expected to last longer than 2 to 3 weeks zinc phosphate cement can be used to increase retention of the temporary restoration. Shade selection: Shade selection CAD/CAM: CAD/CAM CAD/CAM: CAD/CAM Before, performing any restorations it was all about mostly the laboratory procedures and it required long time for the patient to wait and continuous follow up by the dentist. Nowadays there is a solution to make an exact fitting highly esthetical restoration just in one visit by the help of an electronic device called CAD/CAM. It all started by an integration of a modern electronics with an bio–medical science. CAD is a software and CAM is the hardware, by which it is an infra red scanning digital camera that scans a tooth surface that needs a restoration and sends a computed information to the P.C, that processed data and sends it to a robotic restoration milling machine, that cut precisely to fabricate a restoration in needed shade and material. CAD/CAM is also known as a micro milling device. CAD/CAM: CAD/CAM Tooth preparations for CAD/CAM inlays must reflect the capabilities of the CAD “Software” and CAM “hardware” milling devices that fabricate the restorations. Laboratory-fabricated indirect systems require the preparation to have a path of draw that allows insertion and removal of the restoration without interferences from undercuts. However, the CAD/CAM system automatically "blocks out" any undercuts during the process to eliminate any mishaps . CAD/CAM steps: The patient is examined and prepared Anesthesia is performed Isolation with a rubber dam Tooth preparation is carried out. Reflective powder is adapted on a prepared tooth surface. Fabrication steps: Fabrication steps The dentist prepares the tooth the use scanning device to collect information on the shape of the preparation this step is termed optical impression. The system project an image of the preparation and surrounding structure on a monitor allowing the dentist to use the CAD portion of the system to design the restoration the operator must input and or confirm the boundaries of the restoration the gingival margins and the proximal contact. Fabrication steps: Fabrication steps Once the restoration has been designed the computer a micro milling device (CAM) portion which mills the restoration out of the block of high-quality ceramic. The restoration is removed from the milling device ready for try in and cementation. No need for conventional impression. Temporary restoration. Multiple appointment. They are strongest ceramic available for use in dentistry Still a CAD/CAM restorations is a quite expensive but its only away to fabricate custom restorations in a moment. CAD/CAM video: CAD/CAM video Try-in and cementation : Try-in and cementation The try-in and cementation of tooth-colored inlays / onlays are more demanding than that for cast metal restorations because of: The relatively fragile nature of the ceramic or composite material. The requirement of near-perfect moisture control. The use of composite cements. The ceramic or composite inlay is relatively fragile until it is bonded in place with composite cement. Very little pressure should be applied to the restoration during try-in. Because of this fragility, occlusal evaluation and adjustment are delayed until after cementation. Try-in: Try-in Preliminary Steps: The use of the rubber dam should be strongly considered to prevent moisture contamination of the conditioned tooth and/or restoration surfaces during cementation, as well as to improve access and visibility during restoration delivery. After removing the temporary restoration, all the temporary cement is cleaned from preparation walls . Evaluate the fit of the of the restoration use very light pressure if the restoration does not seat completely the most likely cause is an over contoured proximal surface. Correction the position and form of the contact passing dental floss through the contact will indicate the degree of excess contact use abrasive disk to adjusting the proximal contour and contact. When the restoration is completely seated verify the fit around the margin slight excesses should be removed. Cementation : C ementation Acid etching the cavity side of the ceramic or composite restorations with 10 % hydrofluoric acid ,rinsing and dryness. Silane coupling agent is added to the cavity side of the ceramic restoration. Clear plastic matrix strips in each affected proximal and wedged. Acid etching of the walls of cavity preparation. Enamel-dentin bonding agent applied to the wall of the cavity. Cementation : Cementation A dual cured composite cement is inserted into the cavity by syringe and the restoration is immediately inserted into the cavity. E xcess composite cement is removed take care not to remove the composite cement from marginal interface. The restoration is now light cured from occlusal lingual and facial direction 40 to 60 second for each direction. Finishing and polishing: Finishing and polishing Adjustment the occlusal contact Polishing of the restoration Fine grit diamond is used for contour adjustment followed by 30-fluted carbide Further smoothing is accomplished with rubber abrasive point and cups Final polishing is achieved polishing paste applied with a bristle brush Common problems and solutions : Common problems and solutions The most common cause of failure of tooth-colored inlays and onlays is bulk fracture. If bulk fracture occurs, replacement of the restoration is almost always indicated. Minor defects in indirect composite and ceramic restorations can be repaired with relative ease. Of course, before initiating any repair procedure, the operator should determine whether replacement rather than repair is the appropriate treatment. REPAIR OF TOOTH-COLORED INLAYS AND ONLAYS : REPAIR OF TOOTH-COLORED INLAYS AND ONLAYS If repair is deemed to be the appropriate treatment, the dentist should attempt to identify the cause of the problem and correct it if possible. For example, a small fracture due to occlusal trauma may indicate that some adjustment of the opposing occlusion is required. For both composite and ceramic inlays, the repair procedure is initiated by mechanical roughening of the involved surface. While a coarse diamond may be used, a better result is obtained with the use of air-abrading or grit-blasting with aluminum oxide particles and a special intraoral device. For ceramic restorations, the initial mechanical roughening is followed by brief (typically 2 minutes) application of 10% hydrofluoric acid gel. Hydrofluoric acid etches the surface, creating further micro defects to facilitate mechanical bonding. Although many indirect composites contain etch able glass filler particles, hydrofluoric acid treatment of composites is neither necessary nor recommended. REPAIR OF TOOTH-COLORED INLAYS AND ONLAYS : REPAIR OF TOOTH-COLORED INLAYS AND ONLAYS However, a brief application of phosphoric acid may be used to clean the composite surface after roughening. The next step in the repair procedure is application of a silane coupling agent. Silanes mediate chemical bonding between ceramics and resins and also may improve the predictability of resin-resin repairs . The manufacturer's guidelines should be followed when using silanes , as they can differ substantially from one particular product to another . After the silane has been applied, a resin-bonding agent is applied and light-cured. A composite of the appropriate shade is placed, cured, contoured, and polished. Summary : Summary PowerPoint Presentation: Supervisor: Dr.Nashwan Mohamed. Done by : 1. Hussam Al- Selami . Ali Nassar. Fadi Daham . Sadam Al Squor . Thabet Rasheed Alnaqeeb. Abdel Rahman Sabsoob . Nooraldeen Al mufti. Mahmoud Zaitawi . Reference: Art and Science of Operative Dentistry 4th Edition. Fundamentals of operative dentistry a contemporary approach third edition. www.Wikipedia.com Other scientific web sites.